With the aging of the American population, the numbers of adults with peripheral arterial disease (PAD) will increase significantly over the next several decades. Patients with PAD are at increased risk for morbidity and mortality including both cardiovascular and all-cause mortality. While regular physical activity reduces risk for vascular events and is recommended for treatment of PAD patients, few patients meet recommended goals. Exercise programs which increase long-term adherence to walking be an important contribution to PAD treatment. Our internet-based intervention, with an online community builds on a walking enhancement program develop by members of our team and shown to improve adherence among patients with vascular disease such as patients with coronary artery disease (CAD). Using a randomized, controlled trial study design, we propose to test an automated internet-mediated walking program with a social media component, to improving long-term adherence to walking while increasing walking distance, and health-related quality of life (HRQOL), among patients with PAD. Subjects will be randomized to 1 of 4 arms: 1) weekly telephone counseling alone; 2) an internet-based tailored walking intervention; 3) both the weekly telephone counseling and the internet-based tailored walking intervention; and 4) wait-list control. This internet-based walking intervention with a social media component has been shown to increase both adherence to walking and overall walking duration in populations with chronic complex conditions such as coronary artery disease and diabetes. There is a strong need to develop interventions, easily generalizable to a real-world population, to improve the reach of lifestyle interventions which result in improved physical function and adherence to regular exercise among complex medical patients. High risk patients such as those with PAD (a CAD risk equivalent) stand the most to benefit from such programs.